• Reproductive and Developmental Biology
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• v.36 no.1
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• pp.87-93
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• 2012

The purpose of this experiment is to compare the pregnancy rate (PR) according to the state of the ovaries and uterus, according to the number of embryos transferred from cows and heifers and to investigate the method of artificial twin induction with Hanwoo $in$ $vitro$ fertilized (IVF) embryos by embryo transfer (ET). Looking at the PR according to the condition of the ovaries and uterus, the result was not influenced by the condition of the ovaries, but was significantly influenced by the state of the uterus. The PR according to the number of embryos transferred from cows was 36.8%, 53.0%, 50.5% for 1, 2, and 3 embryos respectively, and although there was a higher frequency of twin calves with 3 embryos than with 2, the calving rate was the highest with 2 embryos. In case of heifers, the transfer of 1 embryo showed the best pregnancy and calving rate, and although the PR was similar with 2 embryos (67.7 versus 66.4), in case of 2 embryos transferred there was high frequency of embryonic loss( 6.1%) occurred when a cow was diagnosed at 28 and 53 d after ET, total loss (21.3%; sum of fetal death, abortion and stillbirth after pregnant diagnosis at 60 day).

• Reproductive and Developmental Biology
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• v.36 no.2
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• pp.95-101
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• 2012

The purpose of this experiment was to compare the pregnancy rate (PR) according to the state of the ovaries and uterus, according to the number of embryos transferred from cows and heifers and to investigate the method of artificial twin induction with Hanwoo in vitro fertilized (IVF) embryos by embryo transfer (ET). Looking at the PR according to the condition of the ovaries and uterus, the result was not influenced by the condition of the ovaries, but was significantly influenced by the state of the uterus. The PR according to the number of embryos transferred from cows was 36.8%, 53.0%, 50.5% for 1, 2, and 3 embryos, respectively and although there was a higher frequency of twin calves with 3 embryos than 2, the calving rate was the highest with 2 embryos. In case of heifers, the transfer of 1 embryo showed the best pregnancy and calving rate, and although the PR was similar with 2 embryos (67.7 versus 66.4), in case of 2 embryos transferred there was high frequency of embryonic loss (6.1%) occurred when a cow was diagnosed at 28 and 53 d after ET, total loss (21.3%); sum of fetal death, abortion and stillbirth after pregnant diagnosis at 60 day.

• Journal of Embryo Transfer
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• v.20 no.2
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• pp.163-168
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• 2005

The objective of this study was to produce superior cows by sexual distinction of embryos collected from the donor with pedigree information. Collected embryos distinguished by biopsy using punching or bisection methods and Loop-mediated isothermal amplification of sex-determined DNA for sexing. Six embryos predicted as female were transplanted to recipients and then 2 pregnant cows were normally delivered of calves at 278 and 285 days after embryo transfer. Birth weights of calves named Barani and Borani were 18kg and 25kg, respectively. Adjusted body weights for 90 days were 61.1kg and 88.8kg, respectively. Average daily gains were 0.48kg and 0.71kg, respectively.

• Korean Journal of Animal Reproduction
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• v.19 no.1
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• pp.49-54
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• 1995

This experiments were carried out to investigate the viabilities and the pregnancy rate of frozen-thawed IVF bovine embryos in various media, cryoprotectants and age of embryos produced. Hanwoo oocyte were collected in size of 2~7mm follicles, matured for 20~22hrs at 38.5$^{\circ}C$ in 5% CO2 incubator and then in vitro fertilized with Hanwoo semen. Blastocysts or more developed embryos at Day 7, 8 and 9 were frozen in 1.5 or 1.8M ethylene glycol. Viability of frozen thawed IVF embryos were identified the reformation of blastocoele after thawing and culture for 24~48 hours at 38.5$^{\circ}C$ in 5% CO2 incubator. Production rate of Hanwoo IVF embryos in TCM 199 and CR1aa ws 21.3%(39/183) and 28.1%(41/146), respectively. The viability of frozen thawed IVF embryos was higher rate in 1.8M ethylene glycol and Day 7 embryos than that in 1.5M and Day 8.53 cows out of 100 Hanwoo receipients transfered IVF embryos were pregnant and twin production rate was 26.3%.

• Reproductive and Developmental Biology
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• v.31 no.4
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• pp.235-240
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• 2007

This study was conducted to examine the viability of Korean native striped cattle (Bos namadicus Falconer, Chikso) clone embryos after embryo transfer. Chikso somatic cell nuclear transfer (SCNT) embryos were produced by fusion of ear skin cells derived from a female Chikso with enucleated oocytes matured in vitro for 18-24 hr. After in vitro culture of SCNT embryos for 7 to 8 days, fresh or vitrified blastocysts derived from SCNT were transferred into a uterine horn of recipient cows. Fifteen of total 43 recipients were pregnant at Day 50 and 4 recipients were maintained to term. Three IVF-derived calves and 1 clone Chikso calf were born. Pregnancy rate was higher when fresh embryos were transferred to recipients compared to vitrified embryos, but development to term was not different between both groups. The clone Chikso calf died at 5 days after birth due to the fullness of amniotic fluid in rumen and the infection of umbilical cord. The result of the present study shows that clone Chikso calf can produced from the embryo transfer of SCNT embryos, however, solution of abortion problem is necessary to improve the cloning efficiency.

• Korean Journal of Animal Reproduction
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• v.22 no.2
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• pp.153-161
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• 1998

This study was conducted to examine the viability of nuclear transfer bovine embryos following embryo transfer. Donor embryos were treated with nocodazole to arrest their cell-cycle-stage at mitotic(M) phase. After releasing from nocodazole blastomeres were separated and transferred into the enucleated oocytes(BC), or cultured in medium with aphidicolin. Freshly cleaved blastomeres within 1.5h after cleavage(AC) and non-cleaved ones up to 3h after releasing from nocodazole(NC) were transferred into the enucleated oocytes. Blastocysts derived from nuclear transfer were transferred to Day 7~8 recipient cows. Some blastocysts were vitrified and thawed before embryo transfer. Developmental rates to the blastocyst stage were higher in AC(18.1%, P<0.05) than BC(8.6%) and NC(5.1%). Blastocyst development slightly enhanced with aphidicolin(1~2$\mu\textrm{g}$/ml) treatment(16.9~22.6%) compared to non treated control(11.1%). Survival rate fo vitrified nuclear transfer embryos after thawing was 75%(24/32). Twnety-three vitrified nuclear transfer embryos and 3 fresh ones were transferred to 23 recipients, 6 heads were pregnant and 1 male calf(24 kg) was born from a recipient cow recevied one vitrifiedthawed nuclear transfer embryo at 277 days after embryo transfer. This result suggests that the nuclear transfer embryos can developed to term after vitrification andembryo transfer.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.9
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• pp.1260-1266
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• 2001

The effect of protein supplementation, $O_2$ concentration and co-culture on the development of embryos produced by nuclear transfer using cultured cumulus cell was investigated. Recipient oocytes and cumulus cells were obtained from the ovaries of the slaughtered Hanwoo cows. Donor cumulus cells were cultured in Dulbecco's modified Eagle medium containing 10% fetal bovine serum at 5% $CO_2$ in air at $38.5^{\circ}C$. The 1 to 6 passages of cumulus cells were isolated and used as donor cells. The in vitro matured oocytes were enucleated and then the isolated donor cells were introduced. One $15{\mu}s$ pulse of 180 volts was applied to induce the fusion between karyoplast and cytoplast. The fused embryos were activated with $10{\mu}M$ calcium ionophore for 5 min and 2 mM 6-dimethylaminopurine for 3 h. To examine the effect of protein supplementation, nuclear transfer (NT) embryos were cultured in one of the following 4 treatments : 1) CR1aa + 3 mg/ml BSA for 7 days ; 2) CR1aa + 10% FBS for 7 days ; 3) CR1aa + 1.5 mg/ml BSA + 5% FBS for 7 days ; and 4) CR1aa + 3 mg/ml BSA for first 3 days and then CR1aa + 1.5 mg/ml BSA + 5% FBS for 4 days. Culture took place at 5% $CO_2$, 5% $O_2$ and 90% $N_2$ at $38.5^{\circ}C$. Although there were no significant differences in cleavage rate among different protein supplements, the rates of blastocyst formation were significantly different. When NT embryos were cultured in the medium supplemented with only BSA, they could develop to only morula not to blastocyst. However, when FBS was supplemented, NT embryos developed to blastocyst stage. In order to investigate the effect of $O_2$ concentration and co-culture, NT embryos were cultured in CR1aa + 1.5 mg/ml BSA + 5% FBS with or without cumulus cell co-culture at an atmosphere of 5% $CO_2$ in air (20% $O_2$) or 5% $CO_2$, 5% $O_2$, 90% $N_2$ (5% $O_2$) at $38.5^{\circ}C$ for 7 days. The percentage of blastocyst development was significantly higher when the NT embryos were cultured at an atmosphere of 5% $O_2$ than that of 20% $O_2$ (p<0.05). However, there was no significant difference between with and without cumulus cell co-culture at an atmosphere of 5% $O_2$ or 20% $O_2$. Fifty embryos were transferred to 25 recipients and 5 recipients were pregnant at 100 days. From 5 pregnant cows, only one cow was delivered of female twin. In conclusion, the embryos reconstructed by enucleation of metaphase II oocytes and introduction of the cycling and quiescent cumulus donor cells in Hanwoo had developmental potential to term after embryo transfer to recipient cows.

• Journal of Life Science
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• v.20 no.10
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• pp.1556-1562
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• 2010

This study examined the histopathologic and electron microscopic findings of aborted fetuses from pregnant dairy cows naturally infected with Neospora caninum (N. caninum) at four farms in Gongju city and Yeonki gun of Choongnam province. Systemic subcutaneous edema was observed in the aborted fetuses. The necropsy revealed considerable serosanguinous fluid in the body cavity of the aborted fetuses. Light microscopy showed the infiltration of many inflammatory cells consisting of macrophages, lymphocytes and mononuclear cells, accompanied by congestion, hemorrhage and necrosis of myocardiac cells and hepatocytes in the liver and heart of the aborted fetuses. In the liver, clusters of tachyzoites were formed in the cytoplasm of hepatocytes and the interstitial tissue. In the brain, many tissue cysts of various sizes were observed in the nerve cells and their adjacent areas. Tissue cysts had a round shape and contained a large amount of bradyzoite. In addition, there was diffuse gliosis accompanied by congestion and hemorrhage and focal necrosis in the brain. Infiltration of microglial cells were observed at the periphery of the focal necrosis and perivascular area in the brain. Electron microscopy showed that the tissue cyst wall had a thickness of approximately 1 ${\mu}m$ with an irregular shape. On the interior side, more than 100 bradyzoites with lengths of 2-5 ${\mu}m$ and widths of 1-2 ${\mu}m$ were observed. The nucleus of in the bradyzoites was located approximately 1-1.5 ${\mu}m$ anterior to the posterior tip of the zoite. In the cytoplasm between the nucleus and the posterior tip, there were many amylopectin granules, electron-dense small-sized and electron-thin large-sized round granules, homogeneously electron-dense rhoptries and micronemes oriented perpendicularly to the zoite pellicle. To summarize, tissue cysts were identified on electron microscopy from the aborted fetus from N. caninum seropositive pregnant cow by the ELISA. This led to the confirmed presence of N. caninum.

• Journal of Veterinary Clinics
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• v.27 no.2
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• pp.154-158
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• 2010

Embryo Transfer (ET) is one of the assisted reproductive technologies and a useful tool for improving herds. The purpose of this study is to produce the calves using frozen embryos which were produced in the top one percent Holstein in Canada by ET. One hundred seventeen recipients were used for surrogate mothers and seventy cows were diagnosed to be pregnant. Fifty seven calves were born successfully and thirteen out of them failed to produce viable calves (abortion: 4, stillbirth: 9). Their gestational length, birth body weight and sex ratio for all the viable calves(n = 57) were $278.1{\pm}3.6$ days (range: from 271 to 286 days), $44.0{\pm}3.0\;kg$ (range: from 37 to 49 kg) and 57.9 vs. 42.1 % (male 33 and female 24), respectively. Microsatellite analysis confirmed that they were derived from frozen embryos. In conclusion, this study demonstrated that viable calves derived from frozen-thawed embryos from Canada were born by ET.

• Korean Journal of Veterinary Research
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• v.42 no.3
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• pp.403-410
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• 2002

This study was performed to investigate the general prepartum behavioral ethogram of Bos taurus coreanae (Hanwoo cow). In this study, 4 pregnant cows were placed in a separate area. We recorded the behaviors of the cows using time lapse VCR for 48 hours and analyzed behaviors with the scan point sampling method. We observed maintenance behaviors, social behaviors and ingestion behaviors. During the observation period, the time budgets of behaviors in order of frequency were LD(lying down, 38.2%), ST(standing, 24.7%), EA(eating, 10.7%), WA(walking, 7.2%), LR(lying down rumination, 5.6%), SR(standing rumination, 3.3%), TW(tail wagging, 3.1%) and SG(self grooming, 1.8%). The time budgets of the other behaviors such as PG(pairwise grooming), FC(fly catching) were negligible (<1%).